GDI Plus
How do I create a rounded rect function CreateRoundRectangle(rectangle: TGPRect; radius: integer): TGPGraphicsPath; var path : TGPGraphicsPath; l, t, w, h, d : integer; begin path := TGPGraphicsPath.Create; l := rectangle.X; t := rectangle.y; w := rectangle.Width; h := rectangle.Height; d := radius div 2; // divide by 2 // the lines beween the arcs are automatically added by the path path.AddArc(l, t, d, d, 180, 90); // topleft path.AddArc(l + w - d, t, d, d, 270, 90); // topright path.AddArc(l + w - d, t + h - d, d, d, 0, 90); // bottomright path.AddArc(l, t + h - d, d, d, 90, 90); // bottomleft path.CloseFigure(); result := path; end; How do I flip text procedure TForm29.PaintBox1Paint(Sender: TObject); var graphics : TGPGraphics; FontFamily: TGPFontFamily; Font: TGPFont; SolidBrush: TGPSolidBrush; Matrix : TGPmatrix; SolidPen : TGPPen; r : TGPrectF; GraphicsPath : TGPGraphicsPath; begin graphics := TGPGraphics.Create(PaintBox1.Canvas.handle); FontFamily := TGPFontFamily.Create('Times New Roman'); Font := TGPFont.Create(FontFamily, 32, FontStyleRegular, UnitPixel); SolidBrush := TGPSolidBrush.Create(MakeColor(255, 0, 0, 255)); SolidPen := TGPPen.Create(MakeColor(255, 0, 0, 255)); // graphics.SetTextRenderingHint(TextRenderingHintAntiAlias); // so you can see the box graphics.drawRectangle(SolidPen, MakeRect(0,0,PaintBox1.Width-1, PaintBox1.height-1)); // the normal text offset to the right half of the paintbox graphics.TranslateTransform(PaintBox1.width div 2, 0); graphics.DrawString('AntiAlias', -1, font, MakePoint(0.0, 0.0), solidBrush); // x mirror matrix := TGPMatrix.Create(-1,0,0,1,PaintBox1.width div 2,0); graphics.settransform(matrix); graphics.DrawString('AntiAlias', -1, font, MakePoint(0.0, 0.0), solidBrush); matrix.free; // y mirror matrix := TGPMatrix.Create(1,0,0,-1,PaintBox1.width div 2,PaintBox1.height); graphics.settransform(matrix); graphics.DrawString('AntiAlias', -1, font, MakePoint(0.0, 0.0), solidBrush); matrix.free; // x and y mirror matrix := TGPMatrix.Create(-1,0,0,1,PaintBox1.width div 2,0); graphics.settransform(matrix); matrix.free; matrix := TGPMatrix.Create(1,0,0,-1,0,PaintBox1.height); graphics.multiplytransform(matrix); graphics.DrawString('AntiAlias', -1, font, MakePoint(0.0, 0.0), solidBrush); matrix.free; graphics.Free; FontFamily.Free; Font.Free; SolidBrush.Free; end; How do I Access the pixels in a GDI+ bitmap? This assumes a 32 bit pixel depth. To access the pixels, first lock the bitmap and obtain a TBitmapData. The TBitmapData structure contains information about the bitmap and a pointer to the first scanline. To use the scanline like the TBitmap call the scanline function for the row required. See the example below. function lockBitmap(Bitmap : TGPBitmap) : TBitmapData; var r : TGPRect; begin r.x := 0; r.y := 0; r.width := bitmap.getWidth; r.height := bitmap.getHeight; Bitmap.LockBits(r, ImageLockModeRead or ImageLockModeWrite, Bitmap.GetPixelFormat, result); end; function Scanline(BitmapData : TBitmapData; Row : integer) : PRGBQuad; begin result := bitmapData.Scan0; inc(PByte(result), Row * bitmapData.stride); end; procedure doStuff(Bitmap :TGPBitmap); Var Row, Col : integer; theRow : PRGBQuad; pixel : TRGBQuad; BitmapData : TBitmapData; begin BitmapData := lockBitmap(Bitmap); for Row := 0 to bitmapData.Height - 1 do begin theRow := Scanline(BitmapData, Row); for Col := 0 to Bitmap.getWidth - 1 do begin pixel := theRow^; ..do stuff.. inc(theRow); end; end; Bitmap.UnLockBits(bitmapData); end; How Do I create a rounded rectangle in GDI+ function CreateRoundRectangle(rectangle: TGPRect; radius: integer): TGPGraphicsPath; var path : TGPGraphicsPath; l, t, w, h, d : integer; begin path := TGPGraphicsPath.Create; l := rectangle.X; t := rectangle.y; w := rectangle.Width; h := rectangle.Height; d := radius div 2; // divide by 2 // the lines beween the arcs are automatically added by the path path.AddArc(l, t, d, d, 180, 90); // topleft path.AddArc(l + w - d, t, d, d, 270, 90); // topright path.AddArc(l + w - d, t + h - d, d, d, 0, 90); // bottomright path.AddArc(l, t + h - d, d, d, 90, 90); // bottomleft path.CloseFigure(); result := path; end; See also *GDI *Graphics32 *Delphi 2D Graphics Frequently Asked Questions Category:Code Snippets (Graphics) Category:Source Code Category:Graphics